Liquid crystal display device

ABSTRACT

Disclosed is an LCD device with reduced thickness and bezel width. The LCD device includes a liquid crystal display panel configured to include an upper substrate and a lower substrate that are facing-coupled to each other, a backlight unit configured to include a light guide plate which irradiates light incident from a light source module on the liquid crystal display panel and an optical sheet disposed on the light guide plate, and a coupling member configured to couple the liquid crystal display panel to the light guide plate with the optical sheet therebetween such that a sealed space is provided between the liquid crystal display panel and the light guide plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 14/107,754 filed on Dec. 16, 2013, which claimspriority to Korean Patent Application No. 10-2013-0007857 filed on Jan.24, 2013, which are incorporated by reference herein in their entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to a liquid crystal display (LCD) device,and more particularly, to an LCD device with reduced thickness and bezelwidth.

2. Discussion of the Related Art

LCD devices display an image by using thin film transistors (TFTs) asswitching elements. The LCD devices are widely used as display devicesfor notebook computers, tablet computers, smartphones, portable displaydevices, and various portable information devices, in addition totelevisions or monitors. Since the LCD devices cannot self-emit light,the LCD devices display an image by using light emitted from a backlightunit which is disposed under a liquid crystal display panel.

FIG. 1 is a cross-sectional view schematically illustrating a portion ofa general LCD device.

Referring to FIG. 1, the general LCD device includes a liquid crystaldisplay panel 10, a backlight unit 20, a lower case 30, a guide panel40, and an upper case 50.

The liquid crystal display panel 10 includes a lower substrate 12 and anupper substrate 14 which are coupled to each other with a liquid crystallayer therebetween, and displays an image by using light emitted fromthe backlight unit 20. Polarizing films 16 and 18 are adhered to abottom and top of the liquid crystal display panel 10, respectively.

The backlight unit 20 is disposed under the liquid crystal display panel10, and irradiates light on the bottom of the liquid crystal displaypanel 10. The backlight unit 20 includes: a reflective sheet 21 that isdisposed at the lower caser 30; a light source module 23 that isdisposed at one side of the lower case 30, and emits light; a lightguide plate 25 that is disposed on the reflective sheet 21, and guideslight, which is incident from the light source module 23 onto a lightinput part, toward the liquid crystal display panel 10; a plurality ofoptical sheets 27 that are disposed on the light guide panel 25, andenhance a luminance characteristic of light traveling from the lightguide plate 25 to the liquid crystal display panel 10; and a lightsource housing 29 that supports the light source module 23.

The light source module 23 includes a light emitting diode (LED) arrayboard 23 a and a plurality of LED packages 23 b. The LED array board 23a is disposed at a side wall of the light source housing 29 to face thelight input part of the light guide plate 25. A plurality of drivingpower lines, which respectively supply driving power to the plurality ofLED packages 23 b, are formed at the LED array board 23 a.

The plurality of LED packages 23 b are mounted at certain intervals onthe LED array board 23 a, and emit light with the driving power suppliedfrom the respective driving power lines to irradiate the light havingcertain luminance on the light input part of the light guide plate 25.The light emitted from the plurality of LED packages 23 b is incident onthe light input part of the light guide plate 25, is reflected from andrefracted inside the light guide plate 25, and is irradiated on theliquid crystal display panel 10 through the plurality of optical sheets27 along with light reflected by the reflective sheet 21.

The lower case 30 is provided to have an accommodating space. The lowercase 30 accommodates the backlight unit 20, and supports the guide panel40.

The guide panel 40 is provided in a tetragonal band shape to the supporta bottom edge portion of the liquid crystal display panel 10. The guidepanel 40 includes a panel supporting part, which supports the bottomedge portion of the liquid crystal display panel 10, and a guide sidewall that is formed vertically to the panel supporting part andsurrounds all side walls of the backlight unit 20.

The upper case 50 is provided in a tetragonal band shape in order forone side of the upper case 50 to have a

-shape, and surrounds a top edge portion of the liquid crystal displaypanel 10 and all side surfaces of the guide panel 40.

As described above, the general LCD device includes a certain gap G thatis provided between the bottom of the liquid crystal display panel 10and a top of the optical sheet 27. This, as illustrated in FIGS. 2 and3, is for preventing mura from occurring due to interference betweenelements caused by a bending or twist of the liquid crystal displaypanel 10, the light guide plate 25, and the optical sheet 27. Inparticular, the mura mainly occurs due to a contact between the opticalsheets 27 and the liquid crystal display panel 10 when moisturepenetrates into the gap G at an environment of high temperature andhumidity.

In order to prevent the mura, the optical sheet 27 and the liquidcrystal display panel 10 should be separated from each other by aninterval of 1.5 mm to 2 mm, in which case a thickness T of the LCDdevice increases due to the gap G between the optical sheet 27 and theliquid crystal display panel 10.

Moreover, in the general LCD device, the guide panel 40 maintains aconstant interval between the optical sheet 27 and the liquid crystaldisplay panel 10 and supports the liquid crystal display panel 10, andthe upper case 50 covers the top edge portion of the liquid crystaldisplay panel 10. Therefore, a bezel width W increases due to the guidepanel 40 and the upper case 50.

For this reason, the general LCD device has a limitation in reducing thethickness T and bezel width W thereof.

SUMMARY

Accordingly, the present invention is directed to provide an LCD devicethat substantially obviates one or more problems due to limitations anddisadvantages of the related art.

An aspect of the present invention is directed to provide an LCD devicewith reduced thickness and bezel width.

Additional advantages and features of the invention will be set forth inpart in the description which follows and in part will become apparentto those having ordinary skill in the art upon examination of thefollowing or may be learned from practice of the invention. Theobjectives and other advantages of the invention may be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the invention, as embodied and broadly described herein, there isprovided an LCD device including: a liquid crystal display panelconfigured to include an upper substrate and a lower substrate that arecoupled to face each other; a backlight unit configured to include alight guide plate, which irradiates light incident from a light sourcemodule on the liquid crystal display panel, and an optical sheetdisposed on the light guide plate; and a coupling member configured tocouple the liquid crystal display panel to the light guide plate withthe optical sheet therebetween such that a sealed space is providedbetween the liquid crystal display panel and the light guide plate.

The liquid crystal display panel may further include a lower polarizingmember adhered to the lower substrate to surface-contact an entire areaof a top of the optical sheet in the sealed space, and the couplingmember may be provided between the lower substrate and the light guideplate.

The coupling member may include: a bank provided at a top of the lightguide plate to be separated from each of side surfaces of the lightguide plate and to have a certain height, and configured to support theliquid crystal display panel; and a sealing member provided in a facingspace between the liquid crystal display panel and an edge portion ofthe light guide plate which is an outer portion of the bank, andconfigured to couple the liquid crystal display panel to the light guideplate and seal the outer portion of the bank.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiments of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a cross-sectional view schematically illustrating a portion ofa general LCD device;

FIGS. 2 and 3 are views for describing mora which occur due tointerference between elements in the general LCD device;

FIG. 4 is a cross-sectional view for describing an LCD device accordingto a first embodiment of the present invention;

FIG. 5 is a plane view and a side view for describing a light guideplate and a coupling member of FIG. 4;

FIG. 6 is a cross-sectional view for describing an LCD device accordingto a second embodiment of the present invention;

FIGS. 7A to 7D are views for describing a process of manufacturing theLCD device according to the second embodiment of the present invention;

FIG. 8 is a cross-sectional view for describing an LCD device accordingto a third embodiment of the present invention; and

FIG. 9 is a cross-sectional view for describing an LCD device accordingto a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

The terms described in the specification should be understood asfollows.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “first” and “second” are for differentiating oneelement from the other element, and these elements should not be limitedby these terms.

It will be further understood that the terms “comprises”, “comprising,”,“has”, “having”, “includes” and/or “including”, when used herein,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

The term “at least one” should be understood as including any and allcombinations of one or more of the associated listed items. For example,the meaning of “at least one of a first item, a second item, and a thirditem” denotes the combination of all items proposed from two or more ofthe first item, the second item, and the third item as well as the firstitem, the second item, or the third item.

Hereinafter, embodiments of an LCD device according to the presentinvention will be described in detail with reference to the accompanyingdrawings.

FIG. 4 is a cross-sectional view for describing an LCD device accordingto a first embodiment of the present invention. Referring to FIG. 4, theLCD device according to the first embodiment of the present inventionincludes a liquid crystal display panel 110, a backlight unit 120, acoupling member 130, a lower case 140, a light source case 150, and anupper case 160.

The liquid crystal display panel 110 adjusts a transmittance of lightirradiated from the backlight unit 120, thereby displaying a certainimage. To this end, the liquid crystal display panel 110 includes alower substrate 112, an upper substrate 114, a lower polarizing member116, and an upper film member 118.

The lower substrate 112 includes a plurality of pixels (not shown) whichare respectively formed in a plurality of areas defined by intersectionsbetween a plurality of gate lines (not shown) and a plurality of datalines (not shown).

Each of the plurality of pixels may include a thin film transistor (TFT,not shown) that is connected to a corresponding gate line and acorresponding data line, a pixel electrode that is connected to the TFT,and a common electrode that is formed adjacent to the pixel electrode toreceive a common voltage. The lower substrate 112 generates an electricfield corresponding to a difference voltage between the common voltageand a data voltage applied to each pixel, thereby adjusting a lighttransmittance of a liquid crystal layer.

The upper substrate 114 includes a plurality of color filtersrespectively corresponding to the plurality of pixels which are formedat the lower substrate 112, and is coupled to the lower substrate 112 toface each other with the liquid crystal layer therebetween. A commonelectrode, which receives the common voltage, may be formed at the uppersubstrate 114 depending on a driving mode of the liquid crystal layer.The upper substrate 114 filters, by using the color filters, lightincident through the liquid crystal layer to emit color light to theoutside, thereby enabling the liquid crystal display panel 110 todisplay a certain color image.

The lower substrate 112 and the upper substrate 114 may be provided asvarious types known to those skilled in the art depending on a twistednematic (TN) mode, a vertical alignment (VA) mode, an in-plane switching(IPS) mode, and a fringe field switching (FFS) mode.

The lower polarizing member 116 is adhered to a bottom of the lowersubstrate 112, and polarizes light incident from the backlight unit 120to irradiate the polarized light on the lower substrate 112.

The upper film member 118 may include an upper polarizing member that isadhered to a top of the upper substrate 112, and polarizes light whichis emitted to the outside through the upper substrate 114.

The upper film member 118 may include the upper polarizing member and athree-dimensional (3D) image optical member (not shown) that is disposedon the upper polarizing member. In this case, the liquid crystal displaypanel 110 temporally or spatially divides and displays a left image anda right image depending on a display type of a 3D image, and the 3Dimage optical member separates the left image and the right image toprovide the separated images to a viewer. Here, the 3D image opticalmember is adhered to a top of the upper polarizing member, and mayinclude a retarder film that provides a 3D image based on a polarizingtype to a viewer and a lens film that provides a 3D image based on aglasses-free type to a viewer.

The backlight unit 120 is disposed under the liquid crystal displaypanel 110, and irradiates light onto the bottom of the liquid crystaldisplay panel 110. To this end, the backlight unit 120 includes a lightguide plate 121, a light source module 123, a reflective sheet 125, andan optical sheet 127.

The light guide plate 121 is provided in a flat (or wedge) shape to haveat least one light input part that is provided in at least one sidesurface of the light guide plate 121. The light guide plate 121 guideslight, which is incident through the light input part from the lightsource module 123, toward the liquid crystal display panel 110.

The light source module 123 is disposed to face the light input part ofthe light guide plate 121, and irradiates light on the light guide plate121. To this end, the light source module 123 includes an LED arrayboard 123 a and a plurality of LED packages 123 b.

The LED array board 123 a is a flexible printed circuit board (FPCB)having a flexibility. The LED array board 123 a may be bent in L-shape,and adhered to the lower case 140 by an adhesive member to surround thelight input part of the light guide plate 121 and a bottom edge portionof the light input part. A plurality of driving power lines thatrespectively supply driving power to the plurality of LED packages 123 bare formed at the LED array board 123 a, and are connected to abacklight driving circuit (not shown) through a corresponding signalcable (not shown).

The plurality of LED packages 123 b face the light input part of thelight guide plate 121, and are mounted on the LED array board 123 a tobe separated from each other at certain intervals. The plurality of LEDpackages 123 b emit light with the driving power supplied from therespective driving power lines of the LED array board 123 a to irradiatethe light having certain luminance onto the light input part of thelight guide plate 121. The light emitted from the plurality of LEDpackages 123 b is incident on the light input part of the light guideplate 121, is reflected from and refracted inside the light guide plate121, and is irradiated onto the bottom of the liquid crystal displaypanel 10 through the plurality of optical sheets 127.

The reflective sheet 125 is disposed at a bottom of the light guideplate 121, and reflects light, which is incident through the bottom ofthe light guide plate 121, toward the liquid crystal display panel 110.An edge portion of the reflective sheet 125 may be bent to surround aside surface other than the light input part of the light guide plate121.

The optical sheet 127 is disposed on the light guide plate 121, andenhances a luminance characteristic of light traveling from the lightguide plate 121 to the liquid crystal display panel 110. To this end,the optical sheet 127 may include at least one diffusive sheet and prismsheet.

The coupling member 130 couples the liquid crystal display panel 110 tothe light guide plate 121 to face each other with the optical sheet 127therebetween, in order for a sealed space SS to be provided between theliquid crystal display panel 110 and the light guide plate 121. That is,the coupling member 130 is provided at a top of the light guide plate121 to surround all side surfaces of the optical sheet 127 and the lowerpolarizing member 116 of the liquid crystal display panel 110, and isadhered to the lower substrate 112 of the liquid crystal display panel110. In this case, a height H of the coupling member 130 may be the sameas a total height of the optical sheet 127 and a height of the lowerpolarizing member 116 of the liquid crystal display panel 110, but isnot limited thereto. That is, the coupling member 130 can be compressed(or contracted) by a load of the liquid crystal display panel 110, andthus, the height H of the coupling member 130 may be formed higher thana total height of the optical sheet 127 and the lower polarizing member116 by an amount of compression by the load of the liquid crystaldisplay panel 110. Therefore, the liquid crystal display panel 110 maybe coupled to the light guide plate 121 by the coupling member 130, andthe lower polarizing member 116 of the liquid crystal display panel 110may be disposed in the sealed space SS to surface-contact an entire areaof a top of the optical sheet 127, or disposed at the top of the opticalsheet 127 to have a process gap which is dependent on a compressionamount of the coupling member 130.

The coupling member 130, as illustrated in FIG. 5, is formed at a topedge portion of the light guide plate 121 to have a certain height andwidth, and defines the sealed space SS, in which the optical sheet 127is provided, on the light guide plate 121. Here, the coupling member 130may be formed of one of a double-sided tape, an adhesive resin, and anadhesive pad.

The lower case 140 is provided in a box shape to have an accommodatingspace that accommodates the backlight unit 120.

The light source case 150 is coupled to one side of the lower case 140adjacent the light source module 123, and covers the light input part ofthe light guide plate 121 and a top of the light source module 123facing the liquid crystal display panel 110. That is, the light sourcemodule 150 may be provided in a ⊂-shape to include: a first horizontalpart that is disposed between the light source module 123 and the liquidcrystal display panel 110, and covers the light input part of the lightguide plate 121 and the top of the light source module 123; a verticalpart that is bent vertically from the first horizontal part to surrounda side surface of the lower case 140; and a second horizontal part thatis bent in parallel with the first horizontal part to surround one sideedge portion of a bottom of the lower case 140.

The upper case 160 is provided in a tetragonal band shape to have across-sectional surface having a

-shape, and surrounds a top edge portion of the liquid crystal displaypanel 110, the side surface of the lower case 140, and all side surfacesof the light source case 150. In this case, the upper case 160 may becoupled to the light source case 150 and the side surface of the lowercase 140 by a side coupling scheme using a screw, or may be coupled tothe light source case 150 and the side surface of the lower case 140 bya hook coupling scheme in addition to the screw without being limitedthereto.

A process of manufacturing the LCD device according to the firstembodiment of the present invention will now be described.

First, the coupling member 130 is provided at the top edge portion ofthe light guide plate 121.

Subsequently, the optical sheet 127 is disposed in an optical sheetdisposing area of the light guide plate 121 surrounded by the couplingmember 130.

Subsequently, the light guide plate 121 and the liquid crystal displaypanel 110 are coupled to each other by the coupling member 130 with theoptical sheet 127 therebetween. Therefore, the sealed space SS isprovided between the light guide plate 121 and the liquid crystaldisplay panel 110, and the lower polarizing member 116 of the liquidcrystal display panel 110 is disposed to surface-contact the top of theoptical sheet 127, or disposed on the optical sheet 127 to be separatedfrom the optical sheet 127 by a process gap.

Subsequently, the reflective sheet 125 and the light source module 123are disposed at the lower case 140, and then the light guide plate 121and the liquid crystal display panel 110 which are coupled to face eachother by the coupling member 130 are disposed on the reflective sheet125.

Subsequently, the light source case 150 is assembled to the lower case140.

Subsequently, the upper case 160 is assembled to the lower case 140 andthe light source case 150, and surrounds the top edge portion of theliquid crystal display panel 110, the side surface of the lower case140, and all side surfaces of the light source case 150.

As described above, since the sealed space SS is formed between thelight guide plate 121 and the liquid crystal display panel 110 by thecoupling member 130 and the optical sheet 127 is disposed in the sealedspace SS, the LCD device according to the first embodiment of thepresent invention can prevent a deviation and dislocation of the opticalsheet 127 and interference between elements when testing for amechanical reliability, for example, a vibration and an impact. Also,penetration of a foreign material and moisture is fundamentallyprevented by the sealed space SS, and thus, the LCD device according tothe first embodiment of the present invention can prevent the opticalsheet 127 from being creased due to penetration of the foreign materialand the moisture, and particularly prevent mora from occurring at anenvironment of high temperature and humidity. Also, since the lightguide panel 121 and the liquid crystal display panel 110 are coupled toface each other by the coupling member 130, a guide panel for supportingthe liquid crystal display panel 110 can be removed from the LCD device,thus reducing a thickness T and bezel width W of the LCD device.

As a result, the LCD device according to the first embodiment of thepresent invention can prevent mura from occurring at an environment ofhigh temperature and humidity, and have a thin thickness T and a narrowbezel width W.

FIG. 6 is a cross-sectional view for describing an LCD device accordingto a second embodiment of the present invention, and is configured bychanging a structure of the coupling member. Hereinafter, only aconfiguration of the coupling member will be described.

As seen in FIG. 6, a coupling member 230 of the LCD device according tothe second embodiment of the present invention may include a bank 232and a sealing member 234.

The bank 232 is continuously provided to have a certain width at the topof light guide plate 121 separated from each of the side surfaces of thelight guide plate 121, and defines the sealed space SS between theliquid crystal display panel 110 and the light guide plate 121. The bank232 may contact the lower substrate 112 of the liquid crystal displaypanel 110, or may be formed of a resin member or a pad member at the topof the light guide plate 121 to have a certain gap, but is not limitedthereto. For example, the bank 232 may be formed identical to thecoupling member 130 according to the first embodiment of the presentinvention.

The sealing member 234 is for sealing an outer portion of the bank 232,and is charged into a facing space between the liquid crystal displaypanel 110 and the top edge portion of the light guide plate 121 providedalong the outer portion of the bank 232 to couple the liquid crystaldisplay panel 110 to the light guide plate 121 and seal the sealed spaceSS provided by the bank 232. Here, the bank 232 prevents the sealingmember 234 charged into the facing space from penetrating into thesealed space SS.

The sealing member 234 may be formed of a photocurable sealing materialthat is charged into the facing space by a dispensing method or ajetting method and hardened. For example, the sealing member 234 may beformed an ultraviolet (UV) hardening material so as to enhance aproductivity.

The sealing member 234 is formed by a sealing member formation means(not shown), which includes: a spray nozzle (not shown) that charges asealing material into the facing space; a first light irradiating nozzle(not shown) that is disposed at one side of the spray nozzle, andirradiates light on the sealing material, which is charged into thefacing space by the spray nozzle, to primarily harden the sealingmaterial; and a second light irradiating nozzle (not shown) that isdisposed at one side of the first light irradiation nozzle, andirradiates light on the primarily hardened sealing material to fullyharden the sealing material to form the sealing member 234. The spraynozzle and the first and second light irradiating nozzles may besupported by a nozzle supporting means (not shown), and may form thesealing member 234 while moving along the outer portion of the bank 232according to a movement of the nozzle supporting means. Here, the secondlight irradiating nozzle may not be provided depending on a hardeningtime of the sealing material and a manufacturing process time of thesealing member 234.

FIGS. 7A to 7D are views for describing a process of manufacturing theLCD device according to the second embodiment of the present invention.The process of manufacturing the LCD device according to the secondembodiment of the present invention will now be described with referenceto FIGS. 6 through 7D.

First, as illustrated in FIG. 7A, the bank 232 which is continuous tohave a certain width is provided at the top of the light guide plate 121separated from each side surface of the light guide plate 121.

Subsequently, as illustrated in FIG. 7B, the optical sheet 127 isdisposed on the light guide plate 121 surrounded by the bank 232.

Subsequently, as illustrated in FIG. 7C, the liquid crystal displaypanel 110 is disposed on the light guide plate 121 in which the bank 232is provided and the optical sheet 127 is disposed. In this case, thelower polarizing member 116 of the liquid crystal display panel 110 maybe disposed at the top of the optical sheet 127 to surface-contact theoptical sheet 127, or may be disposed on the optical sheet 127 to beseparated from each other by the process gap.

Subsequently, a sealing member formation means 200 charges a sealingmaterial 234 a into the outer portion of the bank 232 while moving alongthe outer portion of the bank 232, and hardens the sealing material 234a. Therefore, as illustrated in FIG. 7D, the sealing member formationmeans 200 forms the sealing member 234 that seals the facing space whichis formed between the top edge portion of the light guide plate 121 andthe liquid crystal display panel 110 by the outer portion of the bank232, and simultaneously couples the liquid crystal display panel 110 tothe light guide plate 121. Accordingly, the sealed space SS which isdefined by the bank 232 and sealed by the sealing member 234 is formedbetween the liquid crystal display panel 110 and the light guide plate121.

Subsequently, as illustrated in FIG. 6, the reflective sheet 125 and thelight source module 123 are disposed at the lower case 140, and theliquid crystal display panel 110 and the light guide plate 121 which arecoupled to face each other by the coupling member 130 are disposed onthe reflective sheet 125.

Subsequently, the light source case 150 is assembled to the lower case140.

Subsequently, the upper case 160 is assembled to the lower case 140 andthe light source case 150, and surrounds the top edge portion of theliquid crystal display panel 110, the side surface of the lower case140, and all side surfaces of the light source case 150.

FIG. 8 is a cross-sectional view for describing an LCD device accordingto a third embodiment of the present invention.

Referring to FIG. 8, the LCD device according to the third embodiment ofthe present invention includes a liquid crystal display panel 110, abacklight unit 120, a coupling member 130, a lower case 140, a lightsource case 150, and a panel edge protecting member 300. The LCD deviceaccording to the third embodiment of the present invention additionallyincludes the panel edge protecting member 300, and does not include theupper case of the LCD device of FIG. 4 or 6. Thus, only differentelements will be described below.

The panel edge protecting member 300 is provided at a side surface ofthe liquid crystal display panel 110 to have a certain thickness, andsurrounds an edge portion of the liquid crystal display panel 110. Thepanel edge protecting member 300 is provided to surround, except oneside edge portion of a long side of a lower substrate 112 connected to apanel driving circuit (not shown) of the liquid crystal display panel110, the other side edge portion of the long side and both side edgeportions of a short side of the liquid crystal display panel 110. Thatis, the panel edge protecting member 300 may be provided to surround aside surface of the lower substrate 112, a side surface of an uppersubstrate 114, upper and lower corner portions of the lower substrate112 and upper substrate 114 contacting the side surfaces, and a sidesurface of an upper polarizing member 118.

A plane area of the display panel 110 is equal to a plane area of outerdimension of the lower case 140. The panel edge protecting member 300may be formed of a silicon-based or UV hardening-based sealant (orresin), but considering a process tack time, the panel edge protectingmember 300 may be formed of the UV hardening-based sealant. Also, thepanel edge protecting member 300 may have a color (for example, blue,red, bluish green, or black), but the color of the panel edge protectingmember 300 may be selected depending on a design without being limitedthereto. The panel edge protecting member 300 may be formed of a coloredresin or a light blocking resin so as to prevent a side light leakage ofthe liquid crystal display panel 110 due to a total internal reflectionof the lower substrate 112.

An entire top and a side surface of the liquid crystal display panel 110with the panel edge protecting member 300 provided therein are exposedto the outside of the liquid crystal display panel 110 without beingsurrounded by the lower case 140 and the upper case 150. Therefore, afront surface of the liquid crystal display panel 110 has a fully flatshape with no step height, and since an instrument (the upper case or abezel) configuring a front border portion of the liquid crystal displaypanel 110 and a front step height formed by the instrument are allremoved from the LCD device, the LCD device has an enhanced aestheticappearance in terms of a design. Especially, since any instrument is notprovided at a front surface of the liquid crystal display panel 110, adegree of immersion of a user (or a viewer) in a screen can be enhancedin displaying an image.

The lower case 140 is disposed under the liquid crystal display panel110 to accommodate and support the backlight unit 120, but does notsurround a side surface of the liquid crystal display panel 110. To thisend, the lower case 140 includes a supporting part 141 that supports thebacklight unit 120 and a side wall part 143 that is bent from thesupporting part 141 to a bottom of the liquid crystal display panel 110,and surrounds a side surface of the backlight unit 120 and a sidesurface of the coupling member 230.

A top of the side wall part 143 is disposed under the panel edgeprotecting member 300 such that the entire top and the side surface ofthe liquid crystal display panel 110 with the panel edge protectingmember 300 provided therein are exposed to the outside of the LCDdevice.

The light source case 150 is coupled to the lower case 140 such that theentire top and the side surface of the liquid crystal display panel 110with the panel edge protecting member 300 provided therein are exposedto the outside of the LCD device and cover the light source module 123.

In FIG. 8, the coupling member 230 is illustrated as including the bank232 and the sealing member 234, but is not limited thereto. For example,the coupling member 230 may be formed identically to the coupling member130 of FIG. 4.

As described above, the LCD device according to the third embodiment ofthe present invention provides the same effects as those of the LCDdevice according to the first or second embodiment of the presentinvention which has been described above by using the coupling member230, and moreover, by omitting the upper case, the LCD device accordingto the third embodiment of the present invention can realize zero-bezel.Also, the LCD device according to the third embodiment of the presentinvention can protect the externally exposed edge portion of the liquidcrystal display panel 110 from an impact by using the panel edgeprotecting member 300, and prevent the side light leakage.

FIG. 9 is a cross-sectional view for describing an LCD device accordingto a fourth embodiment of the present invention.

Referring to FIG. 9, the LCD device according to the fourth embodimentof the present invention includes a liquid crystal display panel 110, abacklight unit 120, a coupling member 130, a lower case 140, a lightsource case 150, a panel edge protecting member 300, and a gap sealingmember 400. Except that the LCD device according to the fourthembodiment of the present invention additionally includes the gapsealing member 400, the LCD device according to the fourth embodiment ofthe present invention is the same as the LCD device according to thethird embodiment of the present invention, and thus, only the gapsealing member will be described below.

The gap sealing member 400 seals a gap G between the panel edgeprotecting member 300 and a side wall part 143 of the upper case 140,and also seals a gap G between the panel edge protecting member 300 andthe light source case 150. The gap sealing member 400 may be formed ofthe same material as that of the panel edge protecting member 300, andmay be charged into and hardened in the gap G by the same process tocouple the panel edge protecting member 300 to the lower case 140 andthe light source case 150.

In this way, by sealing the gap G, the gap sealing member 400 canprevent a foreign material and moisture from penetrating into the LCDdevice, and reduce deformation such as a bending or twist of the LCDdevice caused to an external force, thus enhancing a rigidity of the LCDdevice by removing the upper case.

As described above, since the optical sheet is disposed in a sealedspace that is formed between the light guide plate and the liquidcrystal display panel, the present invention can prevent a deviation anddislocation of the optical sheet and interference between elements whentesting for a mechanical reliability, for example, a vibration and animpact. Also, penetration of a foreign material and moisture isfundamentally prevented by the sealed space, and thus, the presentinvention can prevent the optical sheet from being creased due topenetration of the foreign material and the moisture, and particularlyprevent mura from occurring at an environment of high temperature andhumidity.

Moreover, since the light guide panel and the liquid crystal displaypanel are coupled to face each other, an instrument such as the guidepanel for supporting the liquid crystal display panel can be removedfrom the LCD device, thus reducing the thickness and bezel width of theLCD device.

Moreover, since the upper case disposed at the front surface of the LCDdevice is not provided, the present invention can provide a zero-bezelLCD device, protect the edge portion of the liquid crystal display panelexposed to the outside by using the panel edge protecting member, andprevent a side light leakage of the LCD device.

Moreover, since the gap sealing member is provided in the gap betweenthe panel edge protecting member and the case, the gap sealing membercan prevent a foreign material and moisture from penetrating into theLCD device, and reduce deformation such as a bending or twist of the LCDdevice caused to an external force, thus enhancing a rigidity of the LCDdevice by removing the upper case.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A liquid crystal display device comprising: aliquid crystal display panel including an upper substrate and a lowersubstrate; a backlight unit including a light source module, a lightguide plate receiving light from the light source module, and an opticalsheet disposed on the light guide plate, the light guide plate having anedge portion which does not overlap with the optical sheet; and acoupling member configured to couple the lower substrate to the edgeportion of the light guide plate such that the optical sheet is disposedin a sealed space defined by the lower substrate, the light guide plate,and the coupling member, wherein the liquid crystal display panelfurther includes a lower polarizing member adhered to the lowersubstrate in the sealed space, and the lower polarizing member incontact with an entire surface area of a top of the optical sheet in thesealed space.
 2. The liquid crystal display device of claim 1, furthercomprising a panel edge protecting member covering edge portions of theupper and lower substrates.
 3. The liquid crystal display device ofclaim 2, wherein the panel edge protecting member is in direct contactwith the edge portions of the upper and lower substrates.
 4. The liquidcrystal display device of claim 3, wherein the liquid crystal displaypanel further includes an upper polarizing member adhered to the uppersubstrate, and the panel edge protecting member is in direct contactwith an edge portion of the upper polarizing member.
 5. The liquidcrystal display device of claim 2, further comprising a lower caseaccommodating the backlight unit.
 6. The liquid crystal display deviceof claim 5, wherein the lower case surrounds at least a portion of thecoupling member.
 7. The liquid crystal display device of claim 5,further comprising a gap sealing member between the panel edgeprotecting member and the lower case.
 8. The liquid crystal displaydevice of claim 5, further comprising a light source case coupled to thelower case, wherein a portion of the light source case is disposedbetween the lower substrate and the light source module.
 9. The liquidcrystal display device of claim 8, wherein the light source casesurrounds at least a portion of the coupling member.
 10. The liquidcrystal display device of claim 9, further comprising a gap sealingmember between the panel edge protecting member and the light sourcecase.
 11. The liquid crystal display device of claim 2, furthercomprising: a lower case accommodating the backlight unit; a lightsource case coupled to the lower case, wherein a portion of the lightsource case is disposed between the lower substrate and the light sourcemodule; and a gap sealing member, wherein a first portion of the gapsealing member is disposed between the panel edge protecting member andthe lower case, and a second portion of the gap sealing member isdisposed between the panel edge protecting member and the light sourcecase.
 12. The liquid crystal display device of claim 1, furthercomprising: a lower case accommodating the backlight unit; a lightsource case coupled to the lower case, wherein a portion of the lightsource case is disposed between the lower substrate and the light sourcemodule; and an upper case surrounding the liquid crystal display panel,the lower case, and the light source case.
 13. The liquid crystaldisplay device of claim 12, wherein a portion of the upper case covers atop edge portion of the liquid crystal display panel.
 14. The liquidcrystal display device of claim 12, wherein the lower case surrounds atleast a portion of the coupling member.
 15. The liquid crystal displaydevice of claim 12, wherein the light source case surrounds at least aportion of the coupling member.
 16. The liquid crystal display device ofclaim 1, wherein the coupling member includes: a bank having a firstside surface facing the sealed space and a second side surface oppositeto the first side surface; and a sealing member contacting the secondside surface of the bank.
 17. The liquid crystal display device of claim1, wherein the sealing member is formed of a photocurable material.